ROS 中CompressedImage消息的发布与订阅_ros compassedimage

背景：某些情况下需要录图像数据的包，非常占空间和带宽，尤其对于一些工业相机图像一张好几兆，每秒30帧的话一份钟好几个G，这时候可以选择的订阅压缩图像，下面直接来个demo。

先订阅一个sensor::Image 消息，然后使用image_transport直接发布图像，会同时产生一个压缩image_compressed/compressed和不压缩的image_compressed图像话题，订阅时直接订阅压缩话题即可。

#include "ros/ros.h"
#include "sensor_msgs/Image.h"
#include "sensor_msgs/CompressedImage.h"
#include "sensor_msgs/image_encodings.h"
#include <image_transport/image_transport.h>
#include <cv_bridge/cv_bridge.h>
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
cv::Mat imgCallback;
image_transport::Publisher image_pub;
static void ImageCallback(const sensor_msgs::ImageConstPtr &msg)
{
    try
    {
      cout<<"FLIR time:"<<msg->header.stamp<<endl;
      return;
      image_pub.publish(msg);
      cv_bridge::CvImagePtr cv_ptr = cv_bridge::toCvCopy(msg,sensor_msgs::image_encodings::BGR8);
      imgCallback = cv_ptr->image;
      cv::imshow("imgCallback",imgCallback);
      cv::waitKey(1);
      cout<<"cv_ptr: "<<cv_ptr->image.cols<<" h: "<<cv_ptr->image.rows<<endl;
      //std::cout<<"Image: "<<msg->width<<" x "<<msg->height<<std::endl;
    }
    catch (cv_bridge::Exception& e)
    {
      //ROS_ERROR("Could not convert from '%s' to 'bgr8'.", msg->encoding.c_str());
      //ROS_ERROR("Could not convert from '%s' to 'bgr8'.",msg->format.c_str());
    }
    //原文链接：https://blog.csdn.net/qq_30460905/article/details/80489841
}
int main(int argc, char **argv)
{
  ros::init(argc, argv, "CompressedImage");
  ros::NodeHandle nh;
  image_transport::ImageTransport it(nh);
  image_transport::Subscriber image_sub;
  std::string image_topic = "usb_cam/image_raw";
  image_sub = it.subscribe(image_topic,10,ImageCallback);
  image_pub = it.advertise("image_compressed",1);
  ros::spin();
  return 0;
}

订阅压缩图像话题消息很简单，直接用ros::Publisher订阅即可

#include "ros/ros.h"
#include "sensor_msgs/CompressedImage.h"
#include "sensor_msgs/image_encodings.h"
#include <cv_bridge/cv_bridge.h>
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
cv::Mat imgCallback;
static void ImageCallback(const sensor_msgs::CompressedImageConstPtr &msg)
{
    try
    {
      cv_bridge::CvImagePtr cv_ptr_compressed = cv_bridge::toCvCopy(msg,sensor_msgs::image_encodings::BGR8);
      imgCallback = cv_ptr_compressed->image;
      cv::imshow("imgCallback",imgCallback);
      cv::waitKey(1);
      cout<<"cv_ptr_compressed: "<<cv_ptr_compressed->image.cols<<" h: "<<cv_ptr_compressed->image.rows<<endl;
    }
    catch (cv_bridge::Exception& e)
    {
      //ROS_ERROR("Could not convert from '%s' to 'bgr8'.", msg->encoding.c_str());
    }
}
int main(int argc, char **argv)
{
  ros::init(argc, argv, "CompressedImage");
  ros::NodeHandle nh;
  ros::Subscriber image_sub;
  std::string image_topic = "image_compressed/compressed";
  image_sub = nh.subscribe(image_topic,10,ImageCallback);
 
  ros::Rate loop_rate(10);
  while (ros::ok())
  {
    ROS_INFO("ROS OK!");
    ros::spinOnce();
    loop_rate.sleep();
  }
  return 0;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8.3)
project(compress_Image)
 
## Compile as C++11, supported in ROS Kinetic and newer
# add_compile_options(-std=c++11)
find_package(catkin REQUIRED COMPONENTS
  roscpp sensor_msgs cv_bridge image_transport
)
find_package(OpenCV 3.3 REQUIRED)
include_directories(${OpenCV_INCLUDE_DIRS})
link_directories(${OpenCV_LIBRARY_DIRS})
catkin_package()
include_directories(
# include
  ${catkin_INCLUDE_DIRS}
)
add_executable(${PROJECT_NAME}_sub src/compress_sub.cpp)
 
## Specify libraries to link a library or executable target against
 target_link_libraries(${PROJECT_NAME}_sub
   ${catkin_LIBRARIES}
   ${OpenCV_LIBRARIES}
 )